Acid merocyanine dyes



Patented Jan. 10, 1950 ACID MEROCYANINEY DYES Leslie G. S. Brooker and Frank L. White, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application July 16, 1945,

Serial No. 605,472

This invention relates to merocyanine dyes and more particularly to merocyanine dyes containing at least oneacid group selected from the group consisting of sulfo SOs I-I) and carboxyl (COOH) groups, in the keto nucleus (1. e. the nucleus containing the carbonyl group of p the auxo-chromophoric group).

Merocyanine dyes are characterized by containing a auxo-chromophore group consisting'of a nitrogen atom (contained in pa heterocyclic nucleus) linkedby a conjugated chain of carbon atoms to the oxygen atom of a keto group, i. e. a carbonyl group. A number of merocyanine dyes are known, and generally speaking, these can be regarded as neutral substances with a tendency to exhibit basic properties. We have now found a new group of merocyanine dyes which are acidic and which behave in photographic silver halide emulsions, in some cases, in a different manner from the known merocyanine dyes.

Our new acidic merocyanine dyes containin the keto nucleus at least one acid group selected from the group consisting of a sulfo group and a carboxyl group, and some of them sensitize photographic silver halide emulsions less strongly (at the same concentration) than do the known merocyanine dyes. In many cases, however, sensitization of a strength comparable to that of the known merocyanine dyes can be obtained by increasing. the concentration of the acid merocyanine'dye in the photographic silver halide emulsion. Our new dyes differ from the known merocyanine dyes in that our dyes leave less stain when sensitized materials containing them are processed.

It is, accordingly, an object of our invention to provide new merocyanine dyes. A further object'is to provide a process. for preparing such merocyanine dyes. A further object is to provide photographic silver halide emulsions sensitized with such dyes. Other objects will become apparent hereinafter.

Our new merocyanine dyes can be represented radical (i. e. an alkyl group substituted or unsubstituted), e. g. methyl, ethyl, n-butyl, isobutyl, allyl, fi-ethoxyethyl, fi-hydroxyethyl, B-acetoXyethyl, carbethoxymethyl, ,B-phenylethyl or benzyl, or R represents an aryl group, e. g. phenyl, L represents amethine group substituted or unsubstituted, n represents a positive integer of from l to 2, 721. represents a positive integer of from 1 to 3, d represents a positive integer of from 1 to 3,

14 Claims. (Cl. 260-240.4)

Q1 represents an oxygen atom, a sulfur atom, or a group of the formula an alkyl group substituted or unsubstituted) or an aryl group, Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing 5 atoms in the ring, e. g. a rhodanine nucleus, a 2-thio2,4(3,5) -oxazoledione nucleus or a 5-pyrazolone nucleus etc., said heterocyclic nucleus containing at least one group selected from the group consisting of sulfo and carboxyl groups, and Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in the heterocyclic ring, e. g. a nucleus of the benzothiazole series, a nucleus of the benzoxazole series, a nucleus of the benzoselenazole series, a nucleus of the a-naphthothiazole series, a nucleus of the fi-naphthothiazole series, a nucleus of the u-naphthoxazole series, a nucleus of the fl-naphthoxazole series, a nucleus of the u-naphthoselenazole series, a nucleus of the B-naphthoselenazole series, a nucleus of the thiazoline series, a nucleus of the simple thiazole series (e. g. 4 methylthiazole, 4 (2 thienyhthiazole, 4-phenylthia'zole, etc.), a nucleus of the simple selenazole series (e. g. 4 methylselenazole, 4-phenylselenazole, etc.), a nucleus of the simple oxazole series (e. g. 4-methyloxazole, 4-phenyloxazole, etc.), a nucleus of the quinoline series, a nucleus of the pyridine series, a nucleus of the 3,3-dialky1indolenine series, etc.

i In accordance with our invention, we prepare merocyanine dyes of the above general formula wherein m represents 1 and. 01 represents 1 (i. e. simple merocyanines) by condensing a cyclammonium quaternary salt containing in the ozor 'y-position (i. e. one of the so-called reactive positions) a thioether group, e. g. an alkylthio, an aralkylthio or an arylthio group, or a halogen atom, e. g. a chlorine, a bromine or an iodine atom, with a heterocyclic compound containing 5 atoms in the ring and containing a ketomethylene (CO-CH2) group in the ring and containing at least one group selected from the group consisting of sulfo and carboxyl groups. This condensation gives simple merocyanine dyes of the following general formula:

wherein R, L, 11, Q and Z have the values set forth above.

'The condensations are advantageously carried out in the presence of a basic condensing agent (i. e. an acid-binding agent) e. g. a tertiary amine, such as pyridine, a trialkylamine or a N-alkyl- .3 V piperidine. Alkali metal carbonates or alkali metal alcoholates can also be employed. A;re-'

action medium can be employed, e. g. a lower molecular weight alcohol, e. g. ethyl, n-propyl, isopropyl, n-butyl or isobutyl alcohol. Heat accelerates the condensations.

Simple merocyanine dyes oiour invention containing a l-quinoline nucleus canalso beprepared by condensing a quinoline-quaternar-y-sa1t containing no substituent in the 4-position, with a heterocyclic compound containing in the heterocyclic ring a lretomethylene group con.-

taining 5 atoms in the ring and containing at least one group selected from the group. consisting of sulfo and carboxylgroups, in the presence of an alcoholic solution of an alkalimetal ,hydroxide, e. g. potassiumhydroxide. Alcohols of the formula C1LH21L+1OH wherein n represents a positive integer of from 1 to 4 are advantageously employed. Y

group inthe ring and containing...at least one aryl) -B-alkylmercaptovin yl group, with a heterocyclic compound containing 5 atoms in the ring and. containing a ketomethylene (--CO-'CH2)= group in the ring and containing at least one group selected from the group consisting of sulfo andcarhoxm groups. The condensations are advantageously carried out in the presence of a basic condensing agent, e. g. a trialkylamine, a

N-alkylpiperidine. or an alkali metal carbonate. A reaction medium-of a lower molecular weight alcohol is advantageously employed.

In accordance with our invention, we prepare merocyanine dyes of the above general formula I wherein m represents 3 and d represents 1 (1. e. merodicarbocyanines) by condensing a cyclammoniumv quaternary salt, containing, in the .uor -position, a 4-arylaminoel,3-butadienyl group, with a heterocyclic compound containing 5 atoms in. .the ring and containing a ketomethylene (COCH2-) group in the heterocyclic. ringand containing, at least one'group selected from;the group consisting of sulfo and carboxyl groups. The. V 4-arylamino-1,3 butadieny1 group is advantageously an acylated 4-arylamino-L3-buta dienyl group, e. g. a '4-acetanilido-1,3-butadienyl group. Thisjcondensation gives m'erodicarbocyadvantageously an ,acylated ,e-arylaminovinyl group, e. g. a ,B-racetanilidovinyl group. Thiscondensation gives merocarbocyanine dyes of following general formula:

l the wherein R, L, 11., Q and Z have the values given above.

The condensations are advantageously carriedout in the presenceof a basiccondensingagent, e. g. a tertiary amine, such as a trimethylamine, triethylamine, dimethylaniline orv a .N-alkylpiperdine. A reaction medium is advantageously employed, e. g. pyridine, or a lower molecular weight alcohol, such as. ethyl, n-propyLisopropyl, n-butyl or isobutyl alcohol. An. alkali metal-carboxylate in a carboxylic anhydride can. also. be employed as basic condensing agent, e.-g. sodium acetate in acetic anhydride. Heat accelerates the condensations.

.Theabove merocarbocyanine dyescan also be prepared by condensing a cyclammoniumquae ternary saltcontainingiri the ocor -position, a -CH2R4 group wherein R4 represents hydrogen, an alkyl group, an alkoxyl group or" an aryloxyl group with an orthoester of a carboxylic acid, e. g. ethyl orthoformate, ethyl orthoacetate,

ethyl .orthopropionate, etc., and a heterocycli'c compound containing 5 atoms in the ring and containing a ketomethylene (-COCI-I2 group in the ring and containing at least one group selected from thegroup consisting of sulfo anine dyes of the following general formula:

wherein R, L, 11 'Qand Zhave the values set forth above.

. The condensations to givemerodicarbocyanine dyes are advantageously carried out in the presence of a-basic condensing agent, e. g. a tertiary amine, such as trimethylamine, triethylamine, dimethylanidine or-a N-alkyipiperidine. A reaction medium is advantageously employed, such as ethyl, -n-propyl,- isopropyl, n-butyl or isobutyl alcohol. An alkali metal carboxylate in a carbocylic anhydride canalso be used as basic condensing agent'e. g. sodium acetate in acetic'anhydride.

In accordance with our invention, we prepare merocyanine dyes or the above I general Formula I, wherein (1 represents 2 or 3 by treating a merocyanine dye of the following general formula: I

wherein R, L, n, m,Q1,R1 and z have the values set forth above, and it represents a positive in teger of from 2 to 3, with an alkyl-salt to obtain a quaternary alkyimercapto compound of the following general formula:

wherein R, L, n, m, Q1,R1 and Z have the values set-forth above, and R2 represents an alcohol radical (i. e. anralkylgr oup substituted or unsubstituted) d-represents a positive integer of from 1 to 2, and X represents an anion. We then condense the quaternarycompound with a heterocyclic compound containing 5 atoms in the ring and containing in. the ring a ketomethylene (-CO--GHz-) group and containing at least one group selected from the group consisting of sulfo and carboxyl groups; This condensation gives complex merocyanine dyes of the following eneral formula:

VII.

wherein R, L, n, m, R1, Q1, Q and Z have the values given above, d represents a positive integer of from 2 to 3.

These condensations which give complex merocyanine dyes are advantageously carried out in the presence of a basic condensing agent, e. g. a trialkylamine, pyridine or a Nl-alkylpiperidine or an alkali metal carbonate,using a lower molecular weight alcohol as reaction medium.

The dyes of our invention which are represented by the following general formula are especially valuable substance for the sensitization of photographic silver halide emulsions:

VIII. I

wherein R, L, n, m, d, Q1, R1 and Z have the values represented above, and R represents a sulfoaryl or carboxyaryl group of the benzene "series and Q represents the non-metallic atoms necessary to complete a rhodanine or a 2-thio- 2,4(3,5)-oxazoledione nucleus. These dyes when employed alone in photographic silver halide emulsions are, generally speaking, good sensitizers. The dyes wherein Q in formula VIII represents the non-metallic atoms necessary to complete a 5-pyrazolone nucleus are not, generally speaking, as efiicacious as sensitizers.

The following examples will serve to illustrate further our new dyes and the manner of obtaining the same.

Example 1.-4 -(3 ethyl 2(3) benzothz'aeolylidene) -3-methyl 1 -(p-sulfophenyl)-5-pyrazo- Zone 2.02 g. (2 mols.) of triethylamine were added to a suspension of 3.99 g. (1 mol.) of 2-phenylmercaptobenzothiazole ethiodide and 2.54 'g. (1 mol.) of 3-methyl-1-(p-sulfophenyl)-5-pyrazolone in 25; cc. of ethyl alcohol, and the mixture was heated at the refluxing temperature for 20 minutes. An excess of hydrogen chloride, in methyl alcohol, was added to the cold reaction mixture. After chilling at 0 C., the dye was collected on a filter and washed with methyl alcohol. The .-yield of crude dye was 65 per cent The .dye was purified by dissolving its triethylamine salt in .ethyl alcohol, filtering thesolution andadding an excess of hydrogen chloride,-in methyl alcohol, to the chilled filtrate. After chilling at 0 C., the ,dye was collected on a filter and washed with methyl alcohol. After a further purification the yield of dye was 51 per cent. The cream-colored crystals had a melting point of 325327 C. with decomposition. This dye did not sensitize a photographic gelatina-silverchlorobromide emulsion in the visual region of the spectrum..- I I Example 2.-3- (p-carboxyphenyl) -5- 3-me'thyl- 2(3) -benzoacazolylidene) -rhol lammz \O=O''NC -COOH 0:1? c=s To crude 2-methylmercaptobenzoxazole methop-toluene-sulfonate, made by heating 1.65 g. (1 mol.) of 2-methylmercaptobenzoxazole and,1.86 g. (1 mol) of methyl p-toluenesulfonate together at about C. for 3 hours, were added 2.53 g. (1 mol.) of 3-(p-carboxyphenyl)rhodanine, 10cc. of ethyl alcohol and 2.02 g. (2 mols.) of triethylamine. The reaction mixture was heated at the refluxing temperature for 30 minutes, later concentrated, and the residue was treated withan excess of acetic acid. The solid was collected on the filter and washed with methyl alcohol. The yield of crude dye was 26 per cent. The dye was purified by dissolving its triethylamine salt in aqueous methyl alcohol and adding an excess of acetic acid to the chilled filtrate. After further chilling at 0 C., the dye was collected on a filter and washed with methyl alcohol. After another purification, the yield was 8 per cent. The light brown crystals had a melting point of 327-328 C. with decomposition and sensitized a photographic gelatino-silver-chlorobromide emulsion to about 490 mu. with maximum sensitivity to about 460 mu.

Example 3.--4-[(5-chloro-3-ethyZ-2(3) benzethiazol'ylidene) -ethylidene']-3 methyl- 1 (psulfophe'nyl) -5-pyrazolone 0.74 g. (1 mol.+5% excess) of triethylamine was added to the suspension of 3.40 g. (1 mol.) of 2 (2 acetanilidovinyl) 5 chlorobenzothiazole ethiodide and 1.78 g. (1 mol.) of 3-methyl-1- (p-sulfophenyl) -5-pyrazolone in 20 cc. of ethyl alcohol and the mixture was heated at the refluxing temperature for 20 minutes. After chilling at 0 C., the solid was collected on a filter and washed with methyl alcohol. The yield of crude dye was 66 per cent. The dye was purified by dissolving its pyridine salt in Water, filtering the solution and adding an excess of concentrated hydrochloric acid to the filtrate. The dye was collected on a filter and washed with methyl alcohol. After a further purificatiointhe yield of .dye was 33 per cent. The brownish crystals had melting point about 315 C. and sensitized a photographic gelatino-silver bromiodide emulsion to about 570 mu. with maximum sensitivity at about 525'mu.

. aHa

1.42 g. (1 mol.) of 5-chloro-3 ethyl-2- thio 9 centrate hydrochloric acid to the filtrate. The dye was collectedon a filter and washed with methylalcohol. After a further purification, the

yield of dye was 50 per cent. The orange crystals had a melting point above 325 C. and sensitized a photographic gelatino-silver-bromiodide emulsion to about 560 mu. with maximum sensi tivity at about 535 mu.

Example 9.4 [(1 -eth'JZ-2(1) -quinolylidene) ethylidenel 3 methyl 1 (p-sullfophenyl) -5- 0.74 g. (1 mol.+5% excess) of triethylamine was added to the suspension of 1.78 g. (1 mol.) of 3-methyl-1(p-sulfophenyl) -5-pyrazolone and 3.11 g. (1 mol.) of 2-(2-acetanilidovinyl)- quinoline ethiodide in 20 cc. of ethyl alcohol and the mixture was heated at the refluxing temperature for 20 minutes. After chilling at C., the solid was collected on the filter and washed with 'methyl alcohol. The yield of crude dye was 70 per cent. The crude dye was dissolved in water as the pyridine salt and the solution was filtered. An excess of concentrated hydrochloric acid was added to the chilled filtrate. After chilling at 0 0., the solid was collected on the filter and washed with methyl alcohol. The residue was dissolved in water as the pyridine salt and the solution was filtered. An excess of hydrogen chloride, dissolved in methyl alcohol, was added to the chilled filtrate. After chilling at 0 C., the dye was collected on the filter and washed with methyl alcohol. The yield of dye Was 47 per cent. The light orange crystals had a melting point above 315 C. and sensitized a photographic gelatino-silver-bromiodide emulsion weakly to about 560 mu.

Example 10.-4 [(1,6-dz'methyl-2(1)-qainolyl f idene ethylidenel 3 methyl 1 (p-sulfoj phenyl) -5-pyrazolone 1.01 g. (2 mols.) of triethylamine was added to the suspension of 2.44 g. (1 mol.) of 2-(2-acetanilidovinyl) 6 methylquinoline metho-ptoluenesulfonate and 1.27 g. (1 mol.) of 3-methyl- 1(p-sulfophenyl)-5-pyrazolone in cc. of ethyl alcohol and the mixture was heated at the refluxing temperature for minutes. An excess of hydrogen chloride, in methyl alcohol, was added to the cold reaction mixture. The solid was collected on a filter and washed with methyl al'cohol. The dye was purified by dissolving its triethylamine salt in methyl alcohol and adding anexcess of hydrogen chloride, in methyl alcohol, to the chilled filtrate. The dye was collected on a filter and washed with methyl alcohol.. ,,After a further purification, the yield of dye was 93 per cent. The dark brownish crys- 10 tals'had a melting point above 310 C'. and sensitized a photographic gelatino-silver-bromiodide emulsion to about 580 mu.

Example 11 .4- (1-ethyl-4(1) -quznolylz'dene) ethyZidehl-B-methyl 1 (p-sulfophenyl) -5- pyrazolone 0.74 g. (1 mol.+5% excess) of triethylamine was addedto'the suspension of 1.78 g. (1 mol.) of 3- methy1-1-(p-sulfophenyl) -5-pyrazolone and 3.11 g. (1 .mol.) of 4-(2-acetanilidovinyD- quinoline ethiodide'in 20 cc. of ethyl alcohol and the mixture was heated at the refluxing temperature for 20 minutes. After chilling at 0 C., the solid was collected on the filter and washed with methyl alcohol. The yield of crude product was 31 per cent. The crude dye was dissolved in water as the pyridine salt and the solution was filtered. An excess of concentrated hydrochloric acid was added to the chilled filtrate. After chilling at 0 C., the solid was collected on the filter and washed with methyl alcohol. The residue was dissolved in water as the pyridine salt and the solution was filtered. An excess of hydrogen chloride, dissolved in methyl alcohol, was added-to-the chilled filtrate. After chilling at 0 C., the dye was collected on the filter and washed with methyl alcohol. The yield of purified dye was 26 per cent. The reddishorange crystals had a melting point above 315 C. and sensitized a photographic gelatino-silverbromiodide emulsion to about 580 mu.

Example 12. 4-[ (3-ethyl-4-methyZ-2 (3) -thiazolylz'dene) ethylz'denel -3 -methyl.- 1 (p-suljophenyl) -5-pyrazolone I 6H: CH5

2.02 g. (2 mols.) of triethylamine was added to the suspension of 4.14 g. (1 mol.) 2(2-acetanilidovinyl) -4-methyl-thiazole ethiodide and 2.54 g. (1 mol.) of 3-methyl-1-(p-sulfophenyl)- 5-pyrazolone in 25 cc. of ethyl alcohol and the mixture was heated at the refluxing temperature for 20 minutes. An excess of hydrogen chloride, dissolved in methyl alcohol, was added to the chilled reaction mixture. The solid was colle'cted on a filter and washed with methyl alcohol. The crude dye was dissolved in water as the pyridine salt and the solution was filtered. An excess of hydrogen chloride, dissolved in methyl alcohol, was added to the chilled filtrate. The dye was collected on a filter and washed with methyl alcohol. After another purification, the yield of dye was 89 per cent and the yellow crystals had a melting point above 315 C. and showed only a trace of sensitization to about 510 mu. in a gelatino-silver-chlorobromide emulsion.

2.02 g. (2 mols.) of triethylamine was added to a suspension of 3.88 g. (l mol.) of 2-(2-acetanilidovinyl) thiazoline methiodide and 2.54 g. (1 mol.) of 3-methyll-(p-sulfophenyl)-5-pyrazolone in 25 cc. of ethyl alcohol and the mixture h a ed a h r fitt em e at e 1 Example 14.-1-- (p-carbomyphenyl) -4-[-(3-ethyl- 2 (3} -benzothiazolylidene) ethylidene] -3-meth;- yZ-S-myrazolone 1.06 g. (1 mol.+5% excess) of triethylamine was added to the suspension of 2.13 g. '(lmol.')' of 3-methyl-l- (p-carboxyphenyl) 5-l' y "azol0ne and .5.0; g. (1. 191.). r z-rzta niaeyi ylle bi qt az le e hi e de' M1 7 cf th l as I and the mixture was Heated at the 'fre us n temperature for 20 minutes." After chilling at 0 C., the solid was collected on a filter and washed with methyl alcohol. The residue was stirred with 150 cc. of. boiling methyl alcohol and L filtered hot. The yield of crude dye was 80 per cent. The dye was purified by dissolving its triethylaminesalt in aqueous methyl alcohol and adding an excess of hydrogen chloride,' in methyl alcohol, o. the chi led filtr e. After chil in at 0? C., the dye was collected on a filter and washed W31 1 5 21 1 9. A fi a 3 1 1 puriaea. than, e yield at dy wa 6 P s at. The crease crystals had" melting point above 31 5f C. and sensitized a photographic gelatino silver-bromiodide'emulsionto about 565 inn. with maximum sensitivity at'about 525 mu. xample ie- ,1 -wfbq llphwwv -l (sema- 2 (3) a bcnzothiazolylidene) -isopropylidcna1- n'tethy(-5-111]iiio lone 12 toluenesuliflll l'eea 0.9 g. (1' 1191;) 0f 15th.? arb zsyp ny l r3-m th rfizpyrazolone in 20: 9. ethyl a qhql and the rea tion mixture was heated t the refluxin t mpera ure for '39 miel e h 09 d mix ure wa stirred ether an the 1 s se te 0 the filte ene washed with wh n 'The r e ue was st red with methyl alcohol and an excessotniperidine. solution was filtered and an excess 01? hydrogen chloride, in methyl alcohol, was added to the chilled filtrate. After further chilling at 0 C., the dye was collected on a filter andwash'ed' with methyl alcohol. The residue was further purified by dissolving its piperidine salt in methyl alcohol; filtering and adding an excess of hydrogen chloride; in methyl alcohoL, to the chilled filtrate. The dye was washed on the filter with methyl alcohol. After another purification, the yield of dye was 83 per cent. The brownish- Yellew e stal h t n m st of 28 39 5 with decomposition and sensitized anh aphic ametee -br m e emuls'i e e a at 551 inn. with maximum sensitivity at about 520 mu.

Eq qmple 6 -ethz/Z. 2(a): henzathiazalr ylidene)e thylidene] 3-methyi 1,-(4-5141104: nqphthyl) 5-py razo lone 0.51 g. (1 mol.) of triethylami'ne was added to the suspension of 2.25 g. ('1 mol.) Of, 2:(2 acuet;v anilidovinyl) -benzothi'azole ethio'dide' and 1.63 g. ('1 mol.) of the sodium salt of 1- (e-sulfo lQ-naph} thyl)-3-methyl-5-pyrazolone in 20 cc. of any; alcohol and the mixture was heated at the refluxing temperature for 30 minutes. The cold reaction mixture was stirred with ether, and the solid was collected on a filterand washed with ethyl alcohol. The residue was suspended in methyl alcohol and. then an excess of piperidine was added. The piperidine salt of the dyedissolved readily in ld me l lC h L terfi t i a e m lled filtrate was treated. with an excess; Qf hydrogen chloride, in methyl alcohol, and the whole lcjhilied at 0 C. The dye was collected on a filter and washed with methyl alcohol. After another purification, the yield of dye was 34 per cent. The light'brownish' crystals had melting point above 310 G and sensitized a photographic gelatinosilver-bromiodide emulsion to about 540 mu.

Example 17.--4-[(3 ethyl-2(3) benzothiazolylidene)isopropylidenel-3 methyl-I-(p-sulfophenyl) -5-pyrazolone l S. V @2115 Example 1 8.4- (1 -ethyZ-2 (1) -fi-naphthothia- 1 zolylidenw isopropylidene] -3 methyl-1 (p -sulfophenyl) -5-pyrazolone. I

This dye was prepared in a 51 per cent yield by using 1.43 g. (1 mol.) of 1-ethyl-2-thioacetylmethylene- 8-naphthothiazoline in place of the 1-ethyl-2 thiobenzoylmethylene-p naphthothiazoline'employed in Example 7. The dull yellow crystals had a melting point above 300 C. with decomposition from about 295 C. This dye sensitized a photographic gelatino-silver-bromiodide emulsion to about 570 mu. with maximum sensitivity at about 530 mu.

Example 19. 3- (p-carboxyphenyl) -5- (Ii-ethyl- 2(3) benzothzazolylidene) ethylz'denelrhodam'ne .01 g. (2 mols.) of triethylamine was added to a suspension of 2.25 g. (1 mol.) of 2-(2-acetanilidovinyDbenzothiazole ethiodide and 1.1 g. (1 mol.) of B-(p-carboxyphenyl) rhodanine in 25 cc. of ethyl alcohol and the reaction mixture was heated at the refluxing temperature for 30 minutes. excess of acetic acid. After chilling at C., the dye was collected on the filter and washed with water. The yield of crude product was 82 per cent. The dye was purified by dissolving its triethylamine salt in methyl alcohol and adding an excess of acetic acid to the chilled filtrate. After chilling at 0 0., the dye was washed on the filter with methyl alcohol. After a further purification, the yield of dye was 55 per cent. The red plates had a melting point of above 300 C. and sensitized a photographic gelatino-silver-bromiodide emulsion to about 650 mu. with maximum sensitivity at about 590 mu.

Example 20.3-(3-carboxy-4-hydroxyphenyl) I -[(3 ethyl-2(3) benzothiazolylidene) ethylidenelrhodanine, pyridine salt lzHs The chilled mixture was treated with an 7 dye-was equal to the theoretical (crude) and 45 per cent after two recrystallizations from pyridine plus methyl alcohol. The red crystals of the pyridine salt of the dye had a melting point of 277-279 O. with decomposition and sensitized a photographic gelatino=-silver-bromiodide emulsion to about 640 mu. with maximum sensitivity at about 590 mu.

Example 21. 5- (3-ethyl-2 (3) -benzothiazolyliden'e) isopropylidenel -3- (p-sulfophenyl') rhodanine Ha S 2 a (2 n methylmercaptopropenyl)benzothiazole etho-p-toluenesulfonate was made by heating 1.2 g. of 3-ethyl-2-thioacetylmethylenebenzothiazoline and 1.43 g. of methyl p-toluenesulfonate together at the temperature of the steam bath for 2 hours. To this crude product were added 1.5 g. of 3-(p-sulfophenyl)rhodanine, 50 cc. of ethyl alcohol and 1.01 g. of triethylamine. The mixture was heated at the refluxing temperature for 30 minutes. After chilling at 0 C., the solid was collected on the filter and washed with ethyl alcohol. The crude dye mixture (2.3 g.) was extracted with seven 200 cc. portions of hot methyl alcohol and the remaining residue was rejected. The yield of dye from all of the extracts was 37 per cent and 20 per cent after another recrystallization from methyl alcohol. The purple crystals had a melting point of above 320 C. and sensitized a photographic gelatino-silver-bromiodide emulsion to about 655 mu. with maximum sensitivity at about 585 mu.

EwampZe 22. 5[ (3-ethyZ-2( -benzothiazolyli dene) ethylidene] 3- (2,5-idisulfophenyl) rhodanine 1.5 g. (3 mols.) of triethylamine was added to the suspension of 2.25 g. (1 mol.) of 2-(2-acetanilidovinyl)benzothiazole ethiodide and 1.85 g. (1 mol.) of 3-(2,5-disulfophenyl) rhodanine in cc. of ethyl alcohol and the reaction mixture was heated at the refluxing temperature for 30 minutes. The mixture was chilled and treated with 3 cc. of concentrated hydrochloric acid. After chilling at 0 C., the dye was collected on a filter and Washed with ethyl alcohol. The yield of dye was 78 per cent crude and 29 per cent after two .recrystallizations from methyl alcohol (100 cc. per gram of dye). The green crystals had a melting point of 204-206 C. with decomposition and sensitized a photographic gelatino-silverbromiodide emulsion to about 635 mu. with maximumsensitivity at about 590 mu.

1101 g. 2 mols.) of triethylamiiiewasaddedw a suspension of 2.2 g. i mom of 2- (2-'la"cetanllidovinyl)benzoxazole ethiodide and 1.1 g. (1 mol.) of 3- (p-carboxyphenyl)rhodanine in 25 cc. of ethyl alcohol and the reaction mixture wasneated at the refluxing temperature for 30 minutes. excess of acetic acid wasaqaed to th'chil ld mixture. After chilling at 0., the solid was -e01- lected on the filter and washed with water. The yield of crude dye was 71 per cent. The dye was purified by dissolving its triethylamine salt in ethyl alcohol andadding an exce soracetic acid to the chilled filtrate. After chilling at 0 6., the dye w'as collected on the filter ahd wa'shedwith ethyl alcohol. After a further purii-lc'ation the yield or dye was 64 per cent. The minute orangplates had a melting point of above 300 0., and sensitized a photographic gelMano-silverbromiodide emulsion to about 615 mu. with maximumsensitivity at about 560 mu.

N zfit 101g. of triethylamine was added to'a suspen; sion of 1.5 g. of 3-(p-sulfopheny1)rhodanine and 2.2 g. of 2- (Z-acetanilidovinyl)benzoxazole ethiodide in 50 cc. of ethyl alcohol and the reaction mixture was heated at the refluxing temperature for 30' minutes. After chilling at 0 0., sfolid was collected on the filter and washed with ethyl alcohol. The residue (1.7 g.) was extracted with hot ethyl alcohol. The yield of dye obtained from this extract was 30 per cent. After another recrystallization from methyl alcohol, the yield of dye was 9 per cent. The red crystals had a melting point above 320 C. and sensitized a photographic gelatino-silver-bromiodide emulsion to about 620 mu. with maximum sensitivity at about 560 mu.

. 'thio -ZA (3,5) -o1;aeoledionc V LzHE 1.0 g. ('2 mols.) of triethylamine was aadecjtc the su pension of 1A g. (1 mol.) of 3-'(p-s'ulfo-' phehy1)=2 -thio-2,4(3,5) oxazoledione and 22' g. (i moi.) cf 2 (2 -acetanilidovinylibehaoxaaol 'e'tliiodide in '30 cc. of ethyl alcchoiand the action mixture was heated at the rename term 0.51 g. (1 mol.) of triethylainlne was-added to a suspension of 2.38 g. (1 mol.) of 2- 01-acetanil ido"-'1,3-butadieny1)'-behzothi' ole ethi'odi'de and 1.27 g. (1 mol.) of s=mahy1=1=(p -Smibphe l)- fi-pyrazolone in 10 cc. of dry pyridine and" the mixture was heated at the refluxing temperature for 5 minutes. The cool reaction mixture was stirred with 250 cc. of ether. After chilliiig at 0 0., the ether layer was decanted; the sticky residue was stirred with a fresh portion of ether. After decanting the ether, the residue was dissolved in methyl alcohol and an excess of acetic acid was added. After chilling at0 G2; thesolid was collected onth funnel and washed with methyl alcohol. The crude product was extracted with successive portions of boiling methyl a1;- cohol in order to remove theblue dye. The yield o f crude dye was 43 per cent. The dye was pu= rifled by dissolving its triethylamine saltin methyl alcohol, filtering the solution and add"- ing an excess of acetic acid to the chilled filtrate: After chilling at 0 C., the dye was collected on a filter and washed with methyl alcohol. After a further purification the yield of dye was 24per cent. The darkgreen crystals had a melting point of 279-280 C. with decomposition and. cam sitize'd a photographic gelatino-silver=bromiodide emulsion weakly to about '700'mu. with maximum sensitivity at about 630 mu.

Example 27.-'.?- (p-carbowyphenyil) -5= E (Q-ethyl- 2(3) benzowazolylidene) 2 butenylidenelrhodanine 0.51 g. (1 mol.) of triethylamlne was added to the suspension of 1.27 g. (1 mol.) of B-(p-carboxyphenybrhodanine and 2.30 g. (1 mol.) of2- l A acetanilido 1.3 butadienylibenzoxazole ethiodide in 15 cc. of pyridine and the him-are was heated at the refluxing temperature for it minutes. The 0001 mixture was 'sthrd with 300 of ether and the whole chille'dat 0 C. The solid was collected on a filter and washed with ether. The residue was dissolved ininethyi a1: cohol and an excess of acetic acid was added. After chilling at of 0., the solid was washed ca the filter with methyl alcohol. The yield of crude dye was 35 per cent. The dye was purified by disaction mixture was stirred with 200 cc. of ether solving its triethylamine salt in methyl alcohol and the whole chilled at C. The solid was (60 cc.) and adding an excess of acetic acid to collected on a filter and washed with ether. The the chilled filtrate. After further chilling, the residue was transferred to a beaker and it was dye was washed on the filter with methyl alcohol. treated with an excess of hydrogen chloride, in After another purification, the yield was 22 per methyl alcohol. After chilling at 0 0., the dye cent. The purplish crystals had a melting point was collected on a filter and washed with methyl of 232-234 C. with decomposition and sensitized al l- The y d f rud dy was 87 p nt.

a photographic gelatino-silver-bromiodide emulhe dye Was pur fied y s olving its triethylsion from ab t 570 mm t b t 7 it 10 amine salt in ethyl alcohol, filtering the solution maximum sensitivity at about 645 mu. a d ad an excess of hydrogen chlo de. in

methyl alcohol, to the chilled. filtrate. After chilling at 0 C., the dye was collected on a filter and washed with methyl alcohol. After a further purification, the yield of dye was 53 per cent.

Example 28. 3-ethyZ-5- (3-ethyl-2 (3) Demon:- azolylidene)ethy'lidene] 2 [3 methyl 5- 0x0 1 (p sulfophenyl) 4 (2 pyrazolinylidene) l-4-thiazolz'clone 1.73 g. (1 mol.) of 5-[(3-ethyl-2 (3) -benzox- The dark green crystals had a melting point of azolylidene)ethylidenel 2 methylmercapto-4- 287-288 C. with decomposition and sensitized a thiazolone etho-p-toluenesulfonate and 0.85 g. photographic gelatino-silver-bromiodide emul- (1 mol.) of 3-methyl-l-(p sulfophenyl) -5-pysion to about 635 mu. with maximum sensitivity razolone were heated together in 10 cc. of pyriat about 600 mu. dine at the refluxing temperature for '7 minutes. The cool reaction mixture was stirred with ether and the whole chilled at 0 C. The ether layer 50 3) i ggi zgzg gzf lgg was decanted and the sticky mass was washed thiazohdone with fresh ether. The residue was treated with 2.59 g. (1 mol.) of 5-[(3-ethyl-2(3)-benzoxazo1- an excess of hydrogen chloride, in methyl aly1idene)ethy1idene]2 -methylmercapto -4-thicohol, and the whole chilled at 0 C. The crude azolone etho-p-toluenesulfonate and 1.27 g. (1 product was collected on a filter and washed with mol.) of 3-(p-carboxyphenyl)rhodanine were methyl alcohol. The residue was stirred with heated together in 25 cc. of pyridine at the reseveral successive portions of methyl alcohol. fluxing temperature for 10 minutes. The cool Example 30.--2-[3-(p-carbomyphenyl) -4-oa:o 2

Theyield of crude dye was 49 per cent. The reaction mixture was stirred with ether and the dye was purified by dissolving its triethylamine solid was collected on the filter and washed with salt in ethyl alcohol, filtering the solution and acetone. The yield of dye Was 29 per cent crude adding an excess of hydrogen chl rid in methyl and 22 per cent after two recrystallizations from alcohol. After chilling at 0 C., the solid was col- 50 Py 0 p gram o y The da re lected on a filter and washed with methyl alcohol. Crystals w a green reflex had a melting Po After a further purification, the yield ofdye was of above and s t ed a photogr p 24 per t, T mackish crystalline pqwder had gelatino-si1ver-bromiodide emulsion from about a melting point of 3l1-3l2 c. with decomposi- 530 to about 650 new with maximum Sensition and showed a trace of sensitization in a tivity at about 610 gelatino-silver-bromiodjde 1 i t t, In a manner similar to that illustrated in the 550 mu. with maximum sensitivity at about 510 fore ing exa pl s, dy containing '4-ph nyl-' mu. thiazole, a-naphthothiazole, benzoselenazole, 4-

methylselenazole, 4-phenylselenazole, a-naphthoazolylidene) ethylz'dene]-2-[3-methyz-5 selenazole, ,B-naphthoselenazole, 4-methyloxazo1e, (p suzfophenyl) 4 p-ymmZZ-nyZidenQLL 4-phenyloxazo1e, a-naphthoxazole, ,B-naphthoxthiazoh-done azole, and pyridine (2- or 4-) nuclei can be pree-iO 1.63 g. (1 mol.) of 5-[(3-ethyl-2(3) -benzopared. Thus, in Examples 1 and 2, 2-phenylthiazolylidene)-ethy1idene]-2 methylmercapto mercaptobenzothiazole ethiodide and 2-methyl- 4-thiazolone ethiodide and 0.85 g. (1 mol.) of 'mercaptobenzoxazole methop-toluenesulfonate S-methyl-l-(p-sulfophenyl)-5|-pyrazolone were can be replaced with a molecularly equivalent heated together in 10 cc. of pyridine at the reamountoi 5-chloro-2-ethylinercaptobenzothiazole fluxing temperature for 7 minutes. The 0001 re- 76 eth'iodide, with a molecularly equivalent amount Example 29.-3-ethyl 5 (3-ethyl-2 (3) -benzothiacid with sulfuric acid and the whole heated at the temperature of the steam bath for 30 minutes. The mixture was chilled at C. and the colorless crystals were collected on the filter.

Example 32.3- (p-carboatyphenyl)rhodanine v 13.7 g. (1 mol.) of p-aminobenzoic acid was suspended in 100 cc. of water and sodium carbonate was added until the resulting solution was neutral to litmus paper. To this solution was added 22.6 g. (1 mol.) of di(carboxymethyl)trithiocarbonate and the reaction mixture was heated at the temperature of the steam bath for about 16 hours. After chilling, the mixture was made acid to Congo red paper with dilute sulfuric acid and the whole further chilled at 0 C. The product was collected on a filter, washed with cold water and then air dried. The yield was 96 per cent.

rhodanine 19.0 g. (1 mol.) of -aminosalicylic acid hydrochloride was dissolved in 100 cc. of water and 10.6 g. of sodium carbonate added slowly. To this neutral solution was added 22.6 g. (1 mol.) of di('carboxymethyl) trithiocarbonate and the reaction mixture was heated at the temperature of the steam bath for about 16 hours. After chilling, the mixture was made acid to Congo red paper with dilute sulfuric acid and the whole further chilled at 0 C. The product was collected 'on a filter, washed with cold water and air dried. The yield was 80 per cent.

Example 34,-3-methyZ-1 (4-sulfo-1-naphthi1lfi- 5-mlrazolone, sodium salt NaO3S -N-'-o=o N\\ /CH2 6.5 g. of l-hydrazinonaphthylene 4-sulfonic acid lErdmann, Ann. 247, 333 (1888) l, 3.5. g. ethyl acetoacetate and 2.3 g. of sodium acetate were heated together in 200 cc. of 50 per cent ethyl alcohol at the refluxing temperature for 18 hours. The mixture was concentrated to about 50 cc. After chilling, the product was collected on a filter and then recrystallized from dilute alcohol. The yield was 5.5 g.

' Example 35.-3-(2,5-disulfophenyl)rhodanine 31.8 g. (1 mol.) of 40 per cent l-aminobenzene- 2,5-disulfonic acid was suspended in 100 cc. of water and 5.3 g. of sodium carbonate was added slowly. To this neutral solution was added 7 g. (1 mol.) of di(carboxymethyl)trithiocarbonate and the reaction mixture was heated at the temperature of the steam bath for 24 hours. After Eli Example 36.-3- (p-sulfophenyl) rhodam'ne S=O CH2 3.6 g. (1 mol.) of sulfanilic acid was suspended in "75 cc. of water and sodium carbonate (about 2.8 g.) was added until the resulting solution was "neutral to litmus paper. To this solution was added 11.3 g. (1 mol.) of di(carboxymethyl)- trithiocarbonate and the reaction mixture was heated at the temperature of the steam bath for 16 hours. After chilling, the mixture was treated with 5 cc. of concentrated sulfuric acid and the whole chilled at 0 C. The product was collected. 'on a filter and washed with cold water. The yield of 3 (p-sulfophenyl)rhodanine was 62 per cent. Thejp'ale yellow crystals had melting point above 300 C.

The di(carboxymethyl)trithiocarbonate employed above was prepared as follows:

A mixture of 908 g. of crystalline sodium sulfide, about 2 l. of water and 287.5 g. of carbon disulfide were stirred mechanically, under reflux, for 16hours. An aqueous solution of 715 g. of chloroaceticacid was neutralized with sodium carbonate and the resulting solution was added to the above mixture and the whole was stirred for -3j" hou'rs.* After making acid to Congo red p-aper'with dilute sulfuric acid, the reaction mixturewaschilled at 0 C. The product was collectedon a filter, washed with cold water and In the preparation of photographic silver halide emulsions containing the acid merocyanine dyes, it is only necessary to disperse the dyes in the emulsions. Ordinarily this is advantageously accomplished by forming a water-soluble salt of the acid merocyanine dye and dissolving the water-soluble salt in water, methanol or ethanol, or'a mixture of water and methanol and ethanol, and dispersing the resulting solution in the emul- 'slon. The salts are advantageously formed by adding to the acid merocyanine dye, wet with a little water, methanol or ethanol, to an alkali metal hydroxide, e. g. sodium or potassium hydroxide, or ammonium hydroxide, or an amine, e. gfmethylamine, ethylamine, dimethylamine, dieth'ylamine, 'trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, pyridine, N-methylpiperidine, n-propylamine,

isopropylamine, butylamine, S-ethoxyethylamine,

etc., and taking up the salt which forms in a suitable solvent, e. g. water, methanol, ethanol, a mixture of water and methanol, a mixture of water and ethanol, etc.

Sensitization by means of our new acid merocyanine dyes is primarily directed to the ordinarily employed gelatino-silver-halide developing-out emulsions, e. g. gelatino-silver-chloride, -chlorobromide, -chlorobromiodide, and -bromio'dide developing-out emulsions'. The

acid dyes or their salts are advantageously addedto the washed, finished emulsions and should;

' solutiomof U the dye (or its salt form) -in-;1an

ofcourse, be suniformly' distributedetliroughout the emulsions. V

: The: concentration; of these compounds in the tions customarily usedf' in the art of emulsion making. To prepare a gelatino-silver-halide emulsionesensitized .with one of our? new dyes, the} following procedure vissati'sfactor-y: aaquanmy of-..the dye in salt -form, isdissolved in ,water, methyl-alcohohethyl alcohol, amixtureot methyl alcohol-aniwater ona mixture of ethyl? alcohol andwater; and a- -v'olume of the solution containing' fromb to100 mg..ofdye.is slowly addedlto about l000 cc. of-agelatino-silver-halide emulsion with-stirring. 'Stirringgis continued untilflthe dye is/uniformly dispersed. With the more:powerful offiour new sensitizing.dyes-, 10- to 50 mg. ;of, dye pert-1M0 cc. of 4 emulsion sufiicesto 'produce ..--the maximum sensitizing efiect with the. ordinary gelatino-silver-halide emulsions. The :;above statements are (only illustrative and are enot to be understoodwaslimiting our inventionineanmsense, as it will. be ,apparent that our;- new dyes: be incorporated by other methods in -manyof {the photographic emulsions customarily employed tin the ;art, such for instance, as by bathing; a plate or -fi1m upon whichean emulsion is coated, in:;a

appropriate solvent-although such asmethod is ordinarilynot :to-be preferred. -Thes'; emulsion claims-are intended to. cover iany 'combination of thesenew-dyes with a .photographicwsilver halide emulsion W :whereby the dyes exert a sensitizing fi ect ontheemulsion. 1 gr v -In the processes 'for preparing-adyes deseribed above; the vl'ieterocycliccompound containingfthe ketomethylene group and containingadatoms in thewheterocyclic ring-Pand :containing' ;a sulfo 1 and/or a =carb oxys group can-be employed its metalror. ammonium .saltform. Actuallyimthe I foregoing-exampleswhere the-eondensations are persecuted -"by Letters :Patent .ofii-thel tlfitd states/i51 J The t merooyanine dyes representedE-by tli'e a following:generalsiformulal' WhereinQR'and R1 each represents a, member sel cted from the .group consistingof ani-Qaikyl 'g' rgoup having the {formulae C11 1H2mj- 1 wherein represents a-positive iintegerofrom "11-; 'to-l wiealidea phony-1'1 group, L' represents a Kmethinee group-sin represents-fia 'positivelinteger: f= -fromwl to represents a positiizesiritegeh of-from -1':to:3;d1-'.ep-, resents ,a positive integer of from 1 to 3, Qrepresents" the non' met'all'ic atoms necessary to complete a heterocyclic nucleus containing five atoms in the heterocyclic ring, three of said atoms beings carbon-atomsone of said atoms being a nitrogen atom and the other of said atoms being 'iselected, froml ,the. group consisting ofean. oxygen at.om",,. a sulfur atom, .and a, ni-t1'ogenaatom 1R represents ,a ,carboxyaryl group .of' .theIbe series ariidithe. sum. metal and, ammonium.v 1t for-ms,btQthese groups and containing 5 atom in the heterocyclicsring, Q1 represents vaI mem er [Selected from, then-group consisting ofJan 019; n

atom, a sulfunatomg and a group of I the formula wherein- R3, rep sents amember, selected-{from t fi. roup consisting ;of an alkizl radicalmendlqan aryl group, and'Z represents the nonmetallic atoms necessary to complete a heterocycl'io nucleus selected from T the {grou consisting 6f thoseof the benzothiaizole s'ei ies, the benzoxazole series, the benzoselenazole'series the e-naphthotiazole series, the p naphthothiazole series, the u-naphthoxazole series, the e-naphthoxazole series, the a naphthoselen'azole series, the flenaphthoselanazole series the thiazqline series, theithiazolej 'series,' the ,;se1en ajzole g'serikesflthejbxseries, the ,quinoline 'series,1the. pyridine a the '3,3adia1kylindo1enine;series. 2.1 The merocarbooyanineI'dyes" which'j aregrep resented by therenewin ,ggeneralirormulaz R N" 'R R;-1 I 'o=ou+,t 'o-,f 0 wherein rR. represents ran ,alkylegroup of.the ,for.- mula CnH2n+1 wherein n- ,represents ..a. ;positive integer of from 1 to 4,; Rerepresents an alkyl group 'of thef'for'riiula CnH-z H wherein n i'epiee sents a positive integer of' -f-rom"1 to 2, Z represents the non-metallicmtoms necessary to complete a heterocyclic nucleus of'the benzoxazole series, Q represents the non-metallic atoms necessary to completea rhodanine nucleus and R5 represents a carboxyaryl group of the benzene series.

5 3. :The: merooarbooyanine dyes 'which are rep- "resented By the following: general formula:

tVherein -R represents an alkyl" group 6f "the formulaCfiHzmi u/"h'ere'i-nn represent a, osititi. integer of from 1 to 4, R6 represents 5in' a'llfyl group -,-.,of--. -the-- formula tcnfiznu wherein represents a'positive integer of from l to 2, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleusofthe benzoxazole series, Q represents the non metallic atoms necessary to complete a 2-'-thio-2', i (3,5)-oxazoledione nucleus and R5 represents a"ca'rboxyary1 group of benz ne e es 4.?"The merocarbocyanine dyes which are' rep- 'resente'dj by the followinggeneral formula:

wherein R represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 4, R6 represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 2, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series, Q represents the non-metallic atoms necessary to complete a 5-pyrazo1one nucleus and R5 represents a carboxyaryl group of the benzene series.

5. The merocarbocyanine dye represented by the following formula:

s $2115 6. The merocarbocyanine dye represented by thefollowing formula:

7. The merocarbocyanine dye represented by the following formula:

8. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt containing in a position selected from the group consisting of cand -positions a group selected from the group consisting of a halogen atom, a thioether group, a 13- arylaminovinyl group and a 4-arylamino-1,3-butadienyl group, with a heterocyclic compound containing a ketomethylene group in the heterocyclic ring, said ketomethylene compound containing 5 atoms in the heterocyclic ring, three of said atoms being carbon atoms, one of said atoms being a nitrogen atom and the other of said atoms being selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom, and containing at least one carboxyaryl group of the benzene series and the alkali metal and ammonium salt forms of these groups.

9. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt containing a thioether group in the a-position, with a heterocyclic compound containing a rhodanine nucleus, said rhodanine nucleus containing at least one carboxyaryl group of the benzene series.

10. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt containing a p-arylaminovinyl in the a-posi- 5 tion, with a heterocyclic compound containing a 2-thio-2,4(3,5) -oxazoledione nucleus, said 2-thio- 2,4(3,5) -oxazoledione nucleus containing at least one carboxyaryl group of the benzene series.

11. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt containing a thioether group in the a-position, with a heterocyclic compound containing a 5-pyrazolone nucleus, said 5-pyrazolone nucleus containing at least one carboxyaryl group of the benzene series.

12. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a benzoxazole quaternary salt containing a thioether group in the inc-position, with a heterocyclic compound containing a rhodanine nucleus, said rhodanine nucleus containing at least one carboxyaryl group of the benzene series.

13. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a benzoxazole quaternary salt containing a ,B-arylaminovinyl in the oa-DOSitiOII, with a heterocyclic compound containing a 2-thio- 2,4(3,5) -oxazoledione nucleus, said 2-thio-2,4- (3,5) -oxazoledione nucleus containing at least one carboxylaryl group of the benzene series.

14. A process for preparing a merocyanine dye comprising condensing, in the presence of a basic condensing agent, a benzothiazole quaternary salt containing a thioether group in the e-position, with a heterocyclic compound containing a 5- pyrazolone nucleus, said 5-pyrazolone nucleus containing at least one carboxyaryl group of the 40 benzene series.

LESLIE G. S. BROOKER. FRANK L. WHITE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,493,747 January 10, 1950 LESLIE G. S. BROOKER ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 21, lines 28 to 30, inclusive, for that portion of the formula reading O\ /OH: read C\ /OH| s s column 24, line 9, for the syllable ings read ing; line 15, after groups insert a comma; lines 15 and 16 strike out and containing 5 atoms in the heterocyclic ring,; line 28, for tiazole read thiazole; line 31, for fl-naphthoselanazole read B-naphthoselenazole;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 23rd day of May, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommiaaimer of Patents. 

1. THE MEROCYANINE DYES REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 